Electroplating with Various Metals. The following receipts furnish the means of coating objects with tin, zinc, brass, German silver, and other metals.

3749. To Electroplate Copper, Brass, or German Silver, with Aluminum

3749.    To Electroplate Copper, Brass, or German Silver, with Aluminum, take equal measures of sulphuric acid and water, or take 1 measure each sulphuric and hydrochloric acids and 2 measures water; add to the water a small quantity of pipe-clay, in the proportion of 5 or 10 grains by weight to every ounce by measure of water (or 1/2 ounce to the pint). Rub the clay with the water until the two are perfectly mixed, then add the acid to the clay solution, and boil the mixture in a covered glass vessel 1 hour. Allow the liquid to settle, take the clear, supernatant solution, while hot, and immerse in it an earthen porous cell, containing a mixture of one measure of sulphuric acid and ten measures of water, together with a rod or plate of amalgamated zinc; take a small Smee's battery of 3 or 4 cells, and connect its positive pole by a wire with the piece of zinc in the porous cell. Having perfectly cleaned the surface of the article to be coated, connect it by a wire with the negative pole of the battery, and immerse it in the hot clay solution; immediately abundance of gas will be evolved from the whole of the immersed surface of the article, and in a few minutes, if the size of the article is adapted to the quantity of the current of electricity passing through it, a fine white deposit of aluminum will appear all over the surface. It may then be taken out, washed quickly in clean water, and wiped dry, and polished ; but if a thicker coating is required, it must be taken out when the deposit becomes dull in appearance, washed, dried, polished, and reimmersed; and this must be repeated at intervals, as often as it becomes dull, until the required thickness is obtained. With small articles it is not absolutely necessary that a separate battery be employed, as the article to be coated may be connected, as in the one cell method (see No. 3669 (Electrotyping by the Single Cell Process)), by a wire with the piece of zinc in the porous cell, and immersed in the outer liquid, when it will receive a deposit, but more slowly than when a battery is employed.

3750. To Electroplate with Tin

3750.     To Electroplate with Tin. Tin is easily deposited from a solution of proto-chloride of tin. If the two poles or electrodes be kept about 2 inches apart, a most beautiful phenomenon may be observed. The decomposition of the solution is so rapid that it shoots out from the negative electrode like feelers, towards the positive, which it reaches in a few seconds. The space between the poles seems like a mass of crystallized threads, and the electric current passes through them without affecting further decomposition. So tender are these metallic threads that when lifted out of the solution they fall upon the plate like cobweb. Seen through a glass they exhibit a beautiful crystalline structure. Tin may also be deposited from its solution in caustic potash or soda.